Pub Date : 2024-05-07DOI: 10.1134/s1027451024020083
E. A. Mazur
Abstract
The processes of generating phonons and electronic excitations by an oriented quantum particle in a crystal are considered. The probabilities of the excitation of phonons and plasmons are calculated. A theory of crystal excitation by a channeled particle with simultaneous photon emission is developed. The probability of a process with the fast particle transitioning into a virtual state after emitting a plasmon, followed by photon emission, is determined. The probability of the process involving photon and plasmon emission is of the same order of magnitude as the probability of the standard process with photon emission alone. The possibility of experimentally detecting the effect is assessed. It is demonstrated that all features of electronic and phonon excitations manifest as components of the radiation spectrum from a fast oriented charged particle in a crystal.
{"title":"On the Generation of Phonons and Electronic Excitations by a Channeled Particle in Crystals","authors":"E. A. Mazur","doi":"10.1134/s1027451024020083","DOIUrl":"https://doi.org/10.1134/s1027451024020083","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The processes of generating phonons and electronic excitations by an oriented quantum particle in a crystal are considered. The probabilities of the excitation of phonons and plasmons are calculated. A theory of crystal excitation by a channeled particle with simultaneous photon emission is developed. The probability of a process with the fast particle transitioning into a virtual state after emitting a plasmon, followed by photon emission, is determined. The probability of the process involving photon and plasmon emission is of the same order of magnitude as the probability of the standard process with photon emission alone. The possibility of experimentally detecting the effect is assessed. It is demonstrated that all features of electronic and phonon excitations manifest as components of the radiation spectrum from a fast oriented charged particle in a crystal.</p>","PeriodicalId":671,"journal":{"name":"Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140883473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.1134/s102745102402040x
L. A. Zhilyakov, V. S. Kulikauskas
Abstract
The work is aimed at studying the properties of the “guiding” effect, namely the possibility of generating electromagnetic radiation when guiding beams of accelerated electrons. In this paper, we discuss a model of motion for the case of electron guiding during the interaction of electron beams with a dielectric surface. It is noted that when an electron beam is pressed against the surface of a dielectric by an external transverse electric field, in this case, due to the guiding effect, the electrons experience transverse vibrations when moving along the surface. Consequently, the movement of electrons in the transverse direction is accelerated and, accordingly, electron beams in the case of guiding should be a source of electromagnetic radiation, similar to the radiation of undulators and wigglers. The numerical estimates carried out in the work using the Larmor formula show that the power of this radiation should have a value sufficient for its experimental detection. This radiation should be of a pulsed nature against the background of continuous radiation. The power of the pulsed radiation must be several orders of magnitude greater than the power of the continuous background radiation.
{"title":"Electromagnetic Radiation of Accelerated Electron Beams During Sliding Interaction with a Dielectric Surface","authors":"L. A. Zhilyakov, V. S. Kulikauskas","doi":"10.1134/s102745102402040x","DOIUrl":"https://doi.org/10.1134/s102745102402040x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The work is aimed at studying the properties of the “guiding” effect, namely the possibility of generating electromagnetic radiation when guiding beams of accelerated electrons. In this paper, we discuss a model of motion for the case of electron guiding during the interaction of electron beams with a dielectric surface. It is noted that when an electron beam is pressed against the surface of a dielectric by an external transverse electric field, in this case, due to the guiding effect, the electrons experience transverse vibrations when moving along the surface. Consequently, the movement of electrons in the transverse direction is accelerated and, accordingly, electron beams in the case of guiding should be a source of electromagnetic radiation, similar to the radiation of undulators and wigglers. The numerical estimates carried out in the work using the Larmor formula show that the power of this radiation should have a value sufficient for its experimental detection. This radiation should be of a pulsed nature against the background of continuous radiation. The power of the pulsed radiation must be several orders of magnitude greater than the power of the continuous background radiation.</p>","PeriodicalId":671,"journal":{"name":"Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140883702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.1134/s1027451024020150
N. V. Novikov, N. G. Chechenin, A. A. Shirokova
Abstract
In this paper, we propose a model to describe the distribution of electrons near the track of a fast ion. The dependence of the fast-electron flux on time, layer depth, and radial variable is modeled taking into account the statistical weight of each trajectory. The pulse duration in the electron-flux distribution was found to be fractions of ps while the radial size of the cylindrical region, where the transport of fast electrons occurs, reaches tens of angstroms.
{"title":"Electron Distribution Near the Fast-Ion Track in Silicon","authors":"N. V. Novikov, N. G. Chechenin, A. A. Shirokova","doi":"10.1134/s1027451024020150","DOIUrl":"https://doi.org/10.1134/s1027451024020150","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In this paper, we propose a model to describe the distribution of electrons near the track of a fast ion. The dependence of the fast-electron flux on time, layer depth, and radial variable is modeled taking into account the statistical weight of each trajectory. The pulse duration in the electron-flux distribution was found to be fractions of ps while the radial size of the cylindrical region, where the transport of fast electrons occurs, reaches tens of angstroms.</p>","PeriodicalId":671,"journal":{"name":"Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140883462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.1134/s1027451024020319
K. P. Karasev, D. A. Strizhkin, A. I. Titov, P. A. Karaseov
Abstract
Molecular dynamic simulation was used to study the processes of molecular 2 to 14 keV C60 ion impact on the (100) Si surface at 0 to 1000 K. Tersoff-ZBL and Airebo interaction potentials were used, and electronic energy loss were taken into account as quasifriction force for fast particles. It is shown that, when single impact events are simulated, the target temperature does not affect the development of the displacement cascade but affects its thermalization and the formation of the crater on the surface. As the energy increases, the carbon penetration depth, the size of the formed crater, and the size of the rim increase. The sputtering coefficient of silicon atoms in this case increases linearly with energy, while for carbon atoms it reaches a steady-state value at 10 keV. A higher number of atomized carbon atoms in single impact events is found using the Tersoff potential compared to the Airebo potential. In the event of cumulative events, the formation of an etch pit is observed at the initial stage followed by carbon film growth. In the case of cumulative ion accumulation, the use of the Airebo potential yields a higher sputtering coefficient than the use of the Tersoff potential. The formation of carbide bonds in the crystal and the increase in their concentration with ion fluence slightly reduce the number of sputtered particles. Therefore, for the correct comparison of simulation results with experiment it is not enough to use the results of single impact event analysis. It is necessary to perform cumulative fluence accumulation simulation.
{"title":"Simulation of Silicon Irradiation with C60 Ions: Unveiling the Role of the Interaction Potential","authors":"K. P. Karasev, D. A. Strizhkin, A. I. Titov, P. A. Karaseov","doi":"10.1134/s1027451024020319","DOIUrl":"https://doi.org/10.1134/s1027451024020319","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Molecular dynamic simulation was used to study the processes of molecular 2 to 14 keV C60 ion impact on the (100) Si surface at 0 to 1000 K. Tersoff-ZBL and Airebo interaction potentials were used, and electronic energy loss were taken into account as quasifriction force for fast particles. It is shown that, when single impact events are simulated, the target temperature does not affect the development of the displacement cascade but affects its thermalization and the formation of the crater on the surface. As the energy increases, the carbon penetration depth, the size of the formed crater, and the size of the rim increase. The sputtering coefficient of silicon atoms in this case increases linearly with energy, while for carbon atoms it reaches a steady-state value at 10 keV. A higher number of atomized carbon atoms in single impact events is found using the Tersoff potential compared to the Airebo potential. In the event of cumulative events, the formation of an etch pit is observed at the initial stage followed by carbon film growth. In the case of cumulative ion accumulation, the use of the Airebo potential yields a higher sputtering coefficient than the use of the Tersoff potential. The formation of carbide bonds in the crystal and the increase in their concentration with ion fluence slightly reduce the number of sputtered particles. Therefore, for the correct comparison of simulation results with experiment it is not enough to use the results of single impact event analysis. It is necessary to perform cumulative fluence accumulation simulation.</p>","PeriodicalId":671,"journal":{"name":"Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140883694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.1134/s1027451024020101
M. M. Mikhailov, V. A. Goronchko, D. S. Fedosov, A. N. Lapin, S. A. Yuryev
Abstract
The results of comparative studies of the phase composition, diffuse reflectance spectra, radiation-induced absorption spectra, and the integral absorption coefficient of solar radiation upon irradiation of micro- and nanopowders of gadolinium oxide are presented. To assess the radiation stability of optical properties, the samples were placed in a chamber of an installation simulating space conditions, where diffuse reflection spectra were recorded in the range of 0.2–2.5 μm in a vacuum of 2 × 10–6 Torr before and after each period of electron irradiation (E = 30 keV, Φ = (1–3) × 1016 cm–2). Micropowders of rare earth elements are used to increase the radiation stability of materials by absorbing free electrons formed in them during irradiation during their transitions from the d- to f-shell. Nanopowders of rare earth elements added to micropowders of various compounds provide an additional mechanism for increasing radiation stability due to the annihilation of primary defects formed during irradiation on nanoparticles. The result obtained in this work is opposite to these mechanisms—the radiation stability of a micropowder is significantly (more than 4 times) higher compared to a nanopowder due to more intense absorption in the ultraviolet region for the nanopowder caused by their own defects. The paper gives an explanation of the results obtained.
{"title":"Comparison of Optical Properties and Radiation Stability of Gd2O3 Micro- and Nanopowders","authors":"M. M. Mikhailov, V. A. Goronchko, D. S. Fedosov, A. N. Lapin, S. A. Yuryev","doi":"10.1134/s1027451024020101","DOIUrl":"https://doi.org/10.1134/s1027451024020101","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The results of comparative studies of the phase composition, diffuse reflectance spectra, radiation-induced absorption spectra, and the integral absorption coefficient of solar radiation upon irradiation of micro- and nanopowders of gadolinium oxide are presented. To assess the radiation stability of optical properties, the samples were placed in a chamber of an installation simulating space conditions, where diffuse reflection spectra were recorded in the range of 0.2–2.5 μm in a vacuum of 2 × 10<sup>–6</sup> Torr before and after each period of electron irradiation (<i>E</i> = 30 keV, Φ = (1–3) × 10<sup>16</sup> cm<sup>–2</sup>). Micropowders of rare earth elements are used to increase the radiation stability of materials by absorbing free electrons formed in them during irradiation during their transitions from the <i>d</i>- to <i>f</i>-shell. Nanopowders of rare earth elements added to micropowders of various compounds provide an additional mechanism for increasing radiation stability due to the annihilation of primary defects formed during irradiation on nanoparticles. The result obtained in this work is opposite to these mechanisms—the radiation stability of a micropowder is significantly (more than 4 times) higher compared to a nanopowder due to more intense absorption in the ultraviolet region for the nanopowder caused by their own defects. The paper gives an explanation of the results obtained.</p>","PeriodicalId":671,"journal":{"name":"Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140883700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.1134/s1027451024020332
V. P. Koshcheev, Yu. N. Shtanov
Abstract
Within the framework of a new approach to the problem of calculating the total energy of a diatomic molecule in first-order perturbation theory, it is shown that the potential-energy screening function is a solution to a diffusion-type equation in which the role of a time variable is played by the mean square of the amplitude of collective oscillations of electrons per degree of freedom. The total energy of a diatomic nitrogen molecule in the ground and excited states is calculated in first-order perturbation theory using tabulated eigenfunctions and eigenvalues of the energy of isolated atoms, which approximate solutions of the Hartree–Fock equation. The reliability of the numerical method for calculating the total energy of a diatomic nitrogen molecule in first-order perturbation theory is verified using an exact solution with an atomic form factor for the screened Coulomb potential. The new approach to the problem of calculating the total energy of a diatomic molecule in first-order perturbation theory does not contain free parameters, but is based on the numerical solution of a system of nonlinear equations.
{"title":"Computer Simulation of the Total Energy and the Screening Function of a Nitrogen Molecule in First-Order Perturbation Theory","authors":"V. P. Koshcheev, Yu. N. Shtanov","doi":"10.1134/s1027451024020332","DOIUrl":"https://doi.org/10.1134/s1027451024020332","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Within the framework of a new approach to the problem of calculating the total energy of a diatomic molecule in first-order perturbation theory, it is shown that the potential-energy screening function is a solution to a diffusion-type equation in which the role of a time variable is played by the mean square of the amplitude of collective oscillations of electrons per degree of freedom. The total energy of a diatomic nitrogen molecule in the ground and excited states is calculated in first-order perturbation theory using tabulated eigenfunctions and eigenvalues of the energy of isolated atoms, which approximate solutions of the Hartree–Fock equation. The reliability of the numerical method for calculating the total energy of a diatomic nitrogen molecule in first-order perturbation theory is verified using an exact solution with an atomic form factor for the screened Coulomb potential. The new approach to the problem of calculating the total energy of a diatomic molecule in first-order perturbation theory does not contain free parameters, but is based on the numerical solution of a system of nonlinear equations.</p>","PeriodicalId":671,"journal":{"name":"Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140883691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.1134/s102745102402006x
Yu. F. Ivanov, V. E. Gromov, T. P. Guseva, A. S. Chapaikin, E. S. Vashchuk, D. A. Romanov
Abstract
The methods of light, scanning, and transmission electron microscopy are used to study the structure, phase composition, and properties of multilayer plasma surfacings made of high-speed steel R18YU in a protective-alloying nitrogen medium, followed by a fourfold high-temperature tempering and additional electron beam processing. After tempering, the deposited layer on the 30KHGSA high-speed steel R18YU has a polycrystalline structure with a cell size of 7–22.5 µm with layers of the second phase along the boundaries and at the joints of the grains. It is shown that the irradiation of surfaised layers with a pulsed electron beam (energy density 30 J/cm2, pulse duration 50 µs, number of pulses 5, and pulse repetition rate 0.3 s–1) leads to the formation of a thin (30–50 µm) surface layer with a cellular crystallization structure. The volume of grains is formed by a solid solution based on α-Fe. Nanoscale (10–45 nm) particles of iron, chromium, and tungsten carbides of complex composition, such as M6C and M23C6, are located in the volume and along the boundaries of the crystallization cells. Fragmentation of the surface layer by a grid of microcracks is revealed, indicating relaxation of thermal stresses formed during high-speed cooling after electron beam processing. The particles have a faceted or globular shape. After irradiation with an electron beam, the wear resistance of the material increases by more than 3 times, while maintaining the microhardness of the modified layer (~5.3 GPa).
{"title":"Structure and Properties of High-Speed Steel Surfaised Layer Irradiated by Pulsed Electron Beam","authors":"Yu. F. Ivanov, V. E. Gromov, T. P. Guseva, A. S. Chapaikin, E. S. Vashchuk, D. A. Romanov","doi":"10.1134/s102745102402006x","DOIUrl":"https://doi.org/10.1134/s102745102402006x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The methods of light, scanning, and transmission electron microscopy are used to study the structure, phase composition, and properties of multilayer plasma surfacings made of high-speed steel R18YU in a protective-alloying nitrogen medium, followed by a fourfold high-temperature tempering and additional electron beam processing. After tempering, the deposited layer on the 30KHGSA high-speed steel R18YU has a polycrystalline structure with a cell size of 7–22.5 µm with layers of the second phase along the boundaries and at the joints of the grains. It is shown that the irradiation of surfaised layers with a pulsed electron beam (energy density 30 J/cm<sup>2</sup>, pulse duration 50 µs, number of pulses 5, and pulse repetition rate 0.3 s<sup>–1</sup>) leads to the formation of a thin (30–50 µm) surface layer with a cellular crystallization structure. The volume of grains is formed by a solid solution based on α-Fe. Nanoscale (10–45 nm) particles of iron, chromium, and tungsten carbides of complex composition, such as M<sub>6</sub>C and M<sub>23</sub>C<sub>6</sub>, are located in the volume and along the boundaries of the crystallization cells. Fragmentation of the surface layer by a grid of microcracks is revealed, indicating relaxation of thermal stresses formed during high-speed cooling after electron beam processing. The particles have a faceted or globular shape. After irradiation with an electron beam, the wear resistance of the material increases by more than 3 times, while maintaining the microhardness of the modified layer (~5.3 GPa).</p>","PeriodicalId":671,"journal":{"name":"Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140883927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.1134/s1027451024020277
V. S. Gornakov, I. V. Shashkov, Yu. P. Kabanov
Abstract
Using Kerr microscopy, the effect of temperature on the displacement of domain boundaries in ultrathin exchange-coupled ferromagnetic layers in heterophase Pt/Co/Pt/Co/Pt films with perpendicular magnetic anisotropy and a nonmagnetic wedge-shaped spacer layer is experimentally studied. The exchange interaction between the Co layers is investigated for spacer-layer thicknesses ranging from 5 to 6 nm within the temperature range of 200 to 300 K. The independent displacement of domain boundaries in the Co layers under the action of a perpendicular magnetic field applied to the sample surface occurs within the range of thicknesses d0 < d < dCR. Throughout the entire temperature range, the displacement of domain boundaries along the Pt wedge results in their stabilization in an equilibrium position. This position depends on the magnitude of the applied field, the thickness of the nonmagnetic spacer layer, and temperature. It is determined by the balance of forces acting on the boundary, including the external field, the effective exchange field between the Co layers, and the coercivity field. Upon the removal of the external field, the domain boundaries relax to the initial state with d = d0 due to the effect of the exchange field. The characteristics of this relaxation depend on the temperature. The study of the mechanism of domain-boundary stabilization near dCR reveal that the critical thickness of the nonmagnetic spacer layer dCR and the coercivity field exhibit oppositely directed dependences on temperature.
摘要 利用克尔显微镜，实验研究了温度对具有垂直磁各向异性和非磁性楔形间隔层的异相铂/钴/铂/钴/铂薄膜中超薄交换耦合铁磁层域界位移的影响。在厚度为 d0 < d < dCR 的范围内，在施加于样品表面的垂直磁场作用下，Co 层的畴界发生独立位移。在整个温度范围内，畴界沿铂楔的位移导致它们稳定在一个平衡位置。这个位置取决于外加磁场的大小、非磁性间隔层的厚度和温度。它是由作用在边界上的力的平衡决定的，包括外场、Co 层之间的有效交换场和矫顽力场。移除外场后，由于交换场的作用，畴界会松弛到 d = d0 的初始状态。这种弛豫的特征取决于温度。对 dCR 附近畴界稳定机制的研究表明，非磁性间隔层的临界厚度 dCR 和矫顽力场对温度的依赖性是相反的。
{"title":"Temperature Dependence of the Kinetics of Domain-Structure Transformation in Heterophase Co/Pt/Co Films","authors":"V. S. Gornakov, I. V. Shashkov, Yu. P. Kabanov","doi":"10.1134/s1027451024020277","DOIUrl":"https://doi.org/10.1134/s1027451024020277","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Using Kerr microscopy, the effect of temperature on the displacement of domain boundaries in ultrathin exchange-coupled ferromagnetic layers in heterophase Pt/Co/Pt/Co/Pt films with perpendicular magnetic anisotropy and a nonmagnetic wedge-shaped spacer layer is experimentally studied. The exchange interaction between the Co layers is investigated for spacer-layer thicknesses ranging from 5 to 6 nm within the temperature range of 200 to 300 K. The independent displacement of domain boundaries in the Co layers under the action of a perpendicular magnetic field applied to the sample surface occurs within the range of thicknesses <i>d</i><sub>0</sub> < <i>d</i> < <i>d</i><sub>CR</sub>. Throughout the entire temperature range, the displacement of domain boundaries along the Pt wedge results in their stabilization in an equilibrium position. This position depends on the magnitude of the applied field, the thickness of the nonmagnetic spacer layer, and temperature. It is determined by the balance of forces acting on the boundary, including the external field, the effective exchange field between the Co layers, and the coercivity field. Upon the removal of the external field, the domain boundaries relax to the initial state with <i>d</i> = <i>d</i><sub>0</sub> due to the effect of the exchange field. The characteristics of this relaxation depend on the temperature. The study of the mechanism of domain-boundary stabilization near <i>d</i><sub>CR</sub> reveal that the critical thickness of the nonmagnetic spacer layer <i>d</i><sub>CR</sub> and the coercivity field exhibit oppositely directed dependences on temperature.</p>","PeriodicalId":671,"journal":{"name":"Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140883695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.1134/s1027451024020046
N. N. Andrianova, A. M. Borisov, M. A. Ovchinnikov, R. Kh. Khisamov, R. R. Mulyukov
Abstract—
The effect of deformation nanostructuring on the ion-beam erosion of copper at a high fluence of irradiation with 30 keV argon ions is experimentally studied. To form an ultrafine-grained structure with a grain size of ~0.4 μm in copper samples with an initial grain size of about 2 μm, deformation nanostructuring by high-pressure torsion is used. It is found that when a layer with a thickness comparable to the grain size is sputtered, a steady-state cone-shaped relief is formed on the copper surface, the appearance of which does not change with increasing irradiation fluence. It is shown that the smaller the grain size in copper, the greater the concentration and the smaller the height of the cones on the surface. The cone inclination angles, close to 82°, as well as the sputtering yield of 9.6 at/ion, are practically independent of the grain size of copper, the thickness of the sputtered layer, and the irradiation fluence. Calculations using the SRIM program show that, when taking into account the redeposition of atoms from the walls of the cones, the sputtering yield of a cone-shaped copper relief Yc is 3.5 times less than the sputtering yield of a single cone, 1.2 times greater than the sputtering yield of a smooth surface, and the value of 9.25 at/ion is close to the experimentally measured one.
{"title":"Effect of Deformation Nanostructuring on the Ion-Beam Erosion of Copper","authors":"N. N. Andrianova, A. M. Borisov, M. A. Ovchinnikov, R. Kh. Khisamov, R. R. Mulyukov","doi":"10.1134/s1027451024020046","DOIUrl":"https://doi.org/10.1134/s1027451024020046","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">\u0000<b>Abstract</b>—</h3><p>The effect of deformation nanostructuring on the ion-beam erosion of copper at a high fluence of irradiation with 30 keV argon ions is experimentally studied. To form an ultrafine-grained structure with a grain size of ~0.4 μm in copper samples with an initial grain size of about 2 μm, deformation nanostructuring by high-pressure torsion is used. It is found that when a layer with a thickness comparable to the grain size is sputtered, a steady-state cone-shaped relief is formed on the copper surface, the appearance of which does not change with increasing irradiation fluence. It is shown that the smaller the grain size in copper, the greater the concentration and the smaller the height of the cones on the surface. The cone inclination angles, close to 82°, as well as the sputtering yield of 9.6 at/ion, are practically independent of the grain size of copper, the thickness of the sputtered layer, and the irradiation fluence. Calculations using the SRIM program show that, when taking into account the redeposition of atoms from the walls of the cones, the sputtering yield of a cone-shaped copper relief <i>Y</i><sub>c</sub> is 3.5 times less than the sputtering yield of a single cone, 1.2 times greater than the sputtering yield of a smooth surface, and the value of 9.25 at/ion is close to the experimentally measured one.</p>","PeriodicalId":671,"journal":{"name":"Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140883490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-07DOI: 10.1134/s1027451024020113
S. A. Mikheev, E. M. Semenova, Yu. G. Pastushenkov, V. P. Tsvetkov, I. V. Tsvetkov
Abstract
The study of the fractal properties of the surface of Nd100 – xFex alloys in a wide range of concentrations х (х = 20–90) was carried out in the framework of the fractal thermodynamics model. To this end, we performed an analysis of scanning electron microscopy images of the surfaces of a series of Nd100 – xFex alloys synthesized by induction melting. A high degree of proximity of the surface structure of all the studied samples, both before and after etching, to fractals is shown. The values of the parameter δ characterizing the relative deviation of the studied samples from the fractal are in the range of 0.017–0.029. Three-dimensional diagrams of the fractal parameters Sf, Tf, Ef, and x and two-dimensional diagrams of the same parameters Sf, Tf, Ef, and x reflecting the nature of the state of the surfaces of Nd100 – xFex alloy samples before and after etching are constructed. For all investigated alloy samples, the values of the parameters of the fractal equations of state are calculated. The correlation of the maximum value of the coercive force Hc = 4.8 kE with the values of fractal entropy Sf = 39.86, fractal temperature Tf = 529, and fractal dimension D = 2.6530 of the Nd100 – xFex alloys at x = 20 has been established.
摘要 在分形热力学模型的框架内，研究了 Nd100 - xFex 合金表面在广泛的浓度 х（х = 20-90）范围内的分形特性。为此，我们对感应熔炼合成的一系列 Nd100 - xFex 合金的表面进行了扫描电子显微镜图像分析。结果表明，所有研究样品在蚀刻前后的表面结构都高度接近分形。表征所研究样品与分形相对偏差的参数 δ 值范围在 0.017-0.029 之间。绘制了分形参数 Sf、Tf、Ef 和 x 的三维图，以及相同参数 Sf、Tf、Ef 和 x 的二维图，反映了蚀刻前后 Nd100 - xFex 合金样品表面状态的性质。计算了所有研究合金样品的分形状态方程参数值。在 x = 20 时，Nd100 - xFex 合金的矫顽力最大值 Hc = 4.8 kE 与分形熵 Sf = 39.86、分形温度 Tf = 529 和分形维度 D = 2.6530 的值之间建立了相关性。
{"title":"Fractal Properties of the Nd100 – xFex Alloys Surface in the Fractal Thermodynamics Model","authors":"S. A. Mikheev, E. M. Semenova, Yu. G. Pastushenkov, V. P. Tsvetkov, I. V. Tsvetkov","doi":"10.1134/s1027451024020113","DOIUrl":"https://doi.org/10.1134/s1027451024020113","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The study of the fractal properties of the surface of Nd<sub>100 – <i>x</i></sub>Fe<sub><i>x</i></sub> alloys in a wide range of concentrations <i>х</i> (<i>х</i> = 20–90) was carried out in the framework of the fractal thermodynamics model. To this end, we performed an analysis of scanning electron microscopy images of the surfaces of a series of Nd<sub>100 – <i>x</i></sub>Fe<sub><i>x</i></sub> alloys synthesized by induction melting. A high degree of proximity of the surface structure of all the studied samples, both before and after etching, to fractals is shown. The values of the parameter δ characterizing the relative deviation of the studied samples from the fractal are in the range of 0.017–0.029. Three-dimensional diagrams of the fractal parameters <i>S</i><sub>f</sub>, <i>T</i><sub>f</sub>, <i>E</i><sub>f</sub>, and <i>x</i> and two-dimensional diagrams of the same parameters <i>S</i><sub>f</sub>, <i>T</i><sub>f</sub>, <i>E</i><sub>f</sub>, and <i>x</i> reflecting the nature of the state of the surfaces of Nd<sub>100 – <i>x</i></sub>Fe<sub><i>x</i></sub> alloy samples before and after etching are constructed. For all investigated alloy samples, the values of the parameters of the fractal equations of state are calculated. The correlation of the maximum value of the coercive force <i>H</i><sub>c</sub> = 4.8 kE with the values of fractal entropy <i>S</i><sub>f</sub> = 39.86, fractal temperature <i>T</i><sub>f</sub> = 529, and fractal dimension <i>D</i> = 2.6530 of the Nd<sub>100 – <i>x</i></sub>Fe<sub><i>x</i></sub> alloys at <i>x</i> = 20 has been established.</p>","PeriodicalId":671,"journal":{"name":"Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140883722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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